Radial brush for grinding and polishing purposes

ABSTRACT

Disclosed is a disk-shaped radial brush for grinding or polishing, including a plate-shaped central body having two side faces and a substantially central opening, and having a plurality of bristles radially extending away from the central body. In order to achieve an assembly of these radial brushes into brush rollers, it is proposed to provide the central body with protrusions on at least one of the side faces and with corresponding receiving members on the other side face. This allows utilizing corresponding radial brushes in brush rollers without slippage of individual radial brushes or without compressing them too much in order to avoid said slippage and thereby deforming them.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

FIELD OF THE INVENTION

The invention relates to a disk-shaped radial brush for grinding orpolishing purposes, comprising a plate-shaped central body having twoside faces and a substantially central opening, and comprising aplurality of bristles radially extending away from the central body.

BACKGROUND OF THE INVENTION

The invention relates to a disk-shaped radial brush for grinding orpolishing purposes, comprising a plate-shaped central body having twoside faces and a substantially central opening, and comprising aplurality of bristles radially extending away from the central body.

Radial brushes of this type are known in the art. They are used in theproduction of jewelry or for manufacturing dental prostheses. There theradial brush is placed with its central opening onto a spindle that isrotatable with high rotational speed and is secured thereto againstslipping and sliding off. Said spindles are also known as mandrels andare provided at one end with a radially protruding, axially fixed collarthat is in a non-rotating manner connected to the spindle for securingradial brushes thereto. Onto the axial end, a flange disk is attached tothe spindle, in particular screwed onto a thread provided thereon, whichusually fixes the radial brush between the protruding collar and theflange disk by clamping.

The bristles of the radial brushes extend radially away from the spindlein the center substantially in a plane perpendicular to the centralspindle axis, in a straight or curved path within said plane.

To fabricate a wider brush roller, a plurality of the disk-shaped radialbrushes are each mounted next to each other onto the spindle by means oftheir substantially central openings and are clamped against each otherand against the collar by means of the flange disk. This creates asubstantially cylindrical brush roller.

When pressing this cylindrical brush roller in a radial direction onto aworkpiece to be polished, the rotation of the spindle must betransferred equally onto all elements of the brush roller, that is, ontoall radial brushes placed on the spindle, such that individual radialbrushes, in particular individual radial brushes positioned in thecenter of the brush roller, are not decelerated by the forces arisingduring polishing and thus slowed down in their rotation. This wouldreduce the polishing rate of these individual, decelerated radialbrushes.

A workpiece that is machined with a brush roller with slipping, that is,not completely co-rotating radial brushes will obtain a convex shapeinstead of a planar shape.

In order to prevent a deceleration of the rotational speed and slippingof individual radial brushes, respectively, and the accompanyingsectional reduction of polishing performance, the axial clamping forcesbetween the individual radial brushes are increased, preferably bymoving, more preferably screwing, the flange disk on the spindleslightly closer towards the collar provided on the spindle. Thereby, theradial brushes are pressed together more strongly in the axial directionof the spindle.

However, a disadvantage for relatively narrow brush rollers is that thebristles at the front faces of the brush rollers extending radially awayfrom the central bodies are bent slightly outwards in the axialdirection when these plate-shaped central bodies are compressed. Insteadof a cylindrical shape, this causes a slight barrel shape of these brushrollers, in particular of narrow brush rollers.

A workpiece that is machined with such a brush roller will obtain acorrespondingly concave shape instead of a planar shape due to the outercontour of the brush roller that is no longer cylindrical, but slightlyconvex and arched or barrel-shaped.

Thus, it is not easy to fabricate an optimal brush roller by assemblinga plurality of disk-shaped radial brushes onto a spindle and subsequentaxial clamping. Often, such brush rollers are tested multiple timesduring assembly, whether the axial clamping force between the individualradial brushes is sufficient to avoid a deceleration of individualradial brushes in the middle of a brush roller and at the same time isnot too large to cause the aforementioned barrel-shaped deformation ofthe brush roller. These multiple tests can be very time-consuming, andit takes a lot of experience to achieve the desired results.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is achieved with a radial brush having thefeatures of the accompanying main claim.

Accordingly, a radial brush comprises a plate-shaped central body havingtwo side faces and a substantially central opening and comprises aplurality of bristles radially extending away from the central body,wherein the central body is provided with protrusions on at least one ofthe side faces and with corresponding receiving members in the form ofrecesses on the other side face.

Further advantageous embodiments may be found in the dependent claims.

The invention has the advantage that, if at least two radial brushes aredisposed on a spindle next to each other, the protrusions on the oneside face of the first radial brush engage with the receiving members ofthe other side face of the second radial brush. This not only achieves africtional connection between the two radial brushes in acircumferential direction, as in the prior art, but also a form fitbetween the adjacent radial brushes.

This has the additional advantage that it allows an easier utilizationof lubricants or cooling agents during grinding. The use of these agentschanges the friction between the adjacent radial brushes on a spindle,said friction being used in the devices known in the art to transfer therotation between the adjacent radial brushes on the spindle. Due to theform fit between adjacent radial brushes, the transfer of rotation isnow independent of the friction.

In a preferred embodiment of the invention, the protrusions on the oneside of the radial brush and the receiving members on the other side ofthe radial brush are circumferentially offset with respect to eachother.

Thereby, axially adjacent radial brushes are positioned only incorrespondingly offset positions relative to each other, that is,slightly skewed in the circumferential direction. This allows a relativepositioning of the bristles of adjacent radial brushes with a specifiedoffset in the circumferential direction with respect to each other.

In a particularly preferred embodiment of the invention, the protrusionsand the receiving members are designed in a substantially elongatedshape.

This is advantageous because the elongated shape facilitates themanufacturing of the radial brushes according to the invention. Theradial brushes according to the invention are made by injection molding.In this case, the material used for fabrication can be molded into theelongated shape of the protrusions and the receiving membersparticularly well.

Preferably, the protrusions and receiving members extend in the radialdirection as well. On one hand, this is advantageous during manufacture,and on the other hand, the transfer of forces in the circumferentialdirection is further improved, which is essential for the (co-)rotationof the individual radial bristles within a brush roller.

It should be noted that in the radial brushes of the invention, theplate-shaped central body and the radially extending bristles areintegrally formed in one piece, in particular made of a thermoplasticpolyurethane (“TPU”) material containing grinding particles.

As already mentioned, a plurality of radial brushes is placed onto aspindle to form a brush roller. Said spindle extends through the centralopening provided in the central body of the radial brush. Morepreferably, the protrusions and receiving members are disposed outsideof an annular region surrounding said central opening.

In this annular region, as in traditional cases, at one end of the brushroller, a flange disk as described above may abut a radial brush at theend of the brush roller, or at the other end of the brush roller, theannular region of a radial brush abuts a collar radially protruding fromthe spindle. Thus, the traditionally employed spindles may also be usedwith the radial brushes according to the invention.

Preferably, the protrusions on the one side of the radial brush may alsobe combined into groups. This allows generating a sort of bar code bymeans of the protrusions, which in turn allows identifying individualradial brushes. For example, radial brushes are distinguished bydifferent bristle strengths, temperature stability or granularity of thegrinding particles therein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Further advantages and features of the invention will be apparent fromthe following description of an exemplary embodiment. Therein:

FIG. 1 is a top view of a radial brush according to the invention;

FIG. 2 is a bottom view of the radial brush of FIG. 1 ;

FIG. 3 is a side view of a spindle with radial brushes disposed thereon;

FIG. 4 is a top view of the spindle of FIG. 3 .

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a top view of a radial brush according to the invention. Shownare a central body 1 and a plurality of bristles 2, 3 radially extendingfrom the central body 1. The illustrated bristles 2, 3 have a curvedshape with the curvature against the direction of rotation. The bristles2, 3 extend in planes parallel to a center plane of the central body 1.

In its center, the central body 1 comprises a round, central opening 4,with which the radial brush is placed onto a rotatable spindle, whichwill be explained in further detail below.

On the first side face 5 shown in the top view of FIG. 1 , the centralopening 4 is surrounded by a circular annular region 6, which issubstantially planar.

Outside of this annular region 6, the first side face 5 is provided withelongated protrusions 7 that are substantially aligned in the radialdirection. They protrude with a substantially triangular cross sectionin the axial direction out of the plane of the first side face 5.

This triangular cross section is substantially congruent to the crosssection of corresponding elongated receiving members 8 that are providedon the other side face 9 of the central body 1 and thus also have asubstantially triangular cross section. The other side face 9 isillustrated in FIG. 2 in the bottom view of the radial brush of FIG. 1 .

When two radial brushes are arranged next to each other, when the one ofthe side faces of the first radial brush abuts the other side face ofthe second radial brush, the protrusions 7 of the one radial brushengage with the correspondingly congruent receiving members 8 of theother radial brush, whereby the two radial brushes are form-fittinglyinterconnected in the circumferential direction.

FIG. 1 also shows, on the first side face 5, which is illustrated hereon top, that the central body 1 integrally transitions to bristles 2that are flush with the top surface of the first side face 5. On theother side face 9, the central body 1 integrally transitions to bristles3 that are flush with the top surface of the other side face 9. Thebristles 2 associated with the first side face 5 and the bristles 3associated with the other side face 9 each have a thicknesscorresponding to approximately half of the thickness of the radial brushand are thus disposed on each side of the center plane of the centralbody and thus of the radial brush.

There are gaps in the circumferential direction between the bristles 2associated with the first side faces 5, as described above. The bristles3 associated with the other side face 9 are substantially centeredwithin these gaps on the other side of the center plane. Viewed from theside, a radial brush thus includes a dense sequence of bristles 2, 3 inthe circumferential direction.

FIG. 3 illustrates how two radial brushes are assembled together to forma brush roller: Shown is a side view of a spindle 10, also known as amandrel. This spindle includes a radially protruding collar 11, which isintegrally connected to the spindle in this exemplary embodiment.

A first radial brush 12 abuts with an annular region 16 against thiscollar 11, when the brush is placed onto the spindle 10 through itscentral opening 4. This annular region 16 surrounds the central opening4 on the other side face 9 of the radial brush 12. The annular region 16has a planar shape to enable a planar abutment against the collar 11 andextends outwards substantially to the radially inner edges of thereceiving members 8.

Subsequently, a second radial brush 13 is placed onto the spindle 10with its central opening 4, whereby the first side face 5 of the firstradial brush 12 comes into contact with the other side face 9 of thesecond radial brush 13. Thereby, the protrusions 7 provided on the firstside face 5 of the first radial brush engage form-fittingly with thecorresponding receiving members 8 on the other side face 9 of the secondradial brush 13, as described above.

As a result, the radial extent of the protrusions 7 is exactly alignedwith the gaps between the bristles 2 associated with the first side face5.

Furthermore, the radial extent of the receiving members 8 is exactlyaligned with the gaps between the bristles 3 associated with the otherside face 9.

This achieves an exact arrangement of the bristles 2, into which thecentral body of the first radial brush 12 transitions on its first sideface 5, in the gaps between the bristles 3, into which the central bodyof the second radial brush 13 transitions on its other side face 9, whenthe protrusions 7 disposed on the first side face of the first radialbrush 12 engage with the receiving members 8 disposed on the other sideface 9 of the second radial brush 13.

This is correspondingly repeated, if more than two radial brushes areassembled onto a spindle into a wider brush roller.

This achieves a uniform distribution of the bristles, both in thecircumferential and the axial direction, even when a plurality ofadjacent radial brushes is assembled into a brush roller.

In order to clamp the first radial brush 12 and the second radial brush13 together, first, the first radial brush 12 is placed onto the spindle10 with its central opening 4. With its annular region 16, it then abutsthe face of the collar 11 disposed on the spindle 10 which faces thefirst brush. Then the second radial brush 13 is placed onto the spindle10 with its central opening 4, and finally, a flange disk 14 is threadedonto the end of the spindle 10 that is illustrated in FIG. 3 on theright side, whereby the flange disk abuts against the annular region 6on the first side face 5 of the second radial brush 13. The annularregion 6 extends around the central opening 4.

The flange disk 14 is embodied in the fashion of a screw and thuscomprises a screw slot for tightening it, as illustrated in FIG. 4 .

When tightened, the flange disk 14 is pressed against the second radialbrush 13, which is pressed against the first radial brush 12, which inturn is pressed against the collar 11 on the spindle 10.

Due to the mutual interconnection of the protrusions 7 and receivingmembers 8 when pressing the first radial brush 12 against the secondradial brush 13, it becomes no longer necessary to excessively tightenthe flange disk 14 onto the end of the spindle 10 in order to achieve arotationally fixed connection of a plurality of adjacent radial brushesby means of friction between the radial brushes 12, 13. This isparticularly relevant, if more than two radial brushes are assembledinto a wider brush roller.

In particular, this limited clamping also prevents unnecessarycompression of the central bodies of adjacent radial brushes 12, 13,which would lead to bending the bristles of axially terminal radialbrushes in an axially outward direction, such that the circumferentialsurface of a corresponding brush roller assembled from a plurality ofradial brushes would be barrel-shaped. Such a brush roller would not besuitable for producing planar surfaces.

At the same time, the mutual interconnection of the protrusions 7 andthe receiving members 8 achieves that all radial brushes within such abrush roller are interconnected in a rotationally fixed manner, andindividual radial brushes, in particular those disposed in the centralregion of the brush roller, are not decelerated and thus slowed in theirrotation, when the brush roller is pressed against a part when in use.

Further, FIG. 1 shows that the individual protrusions 7 are combinedinto groups, in particular, in the illustrated example into three groupsof four protrusions. On one hand, as a matter of fact, tool manufacturemay be simplified by omitting individual protrusions.

On the other hand, this grouping of protrusions allows encoding theradial brushes. This allows labeling the radial brush to distinguish thebristle strengths or temperature stability of a radial brush, or alsothe granularity of the grinding particles used in the radial brush. Inaddition, thickness, outer diameter or diameter of the central openingor other similar characteristics of the radial brush relevant to a usermay be encoded as needed.

Overall, the radial brush according to the invention is a product withsignificant advantages in its application.

LIST OF REFERENCE NUMERALS

-   -   1 Central body    -   2 Bristles    -   3 Bristles    -   4 Central opening    -   5 First side face    -   6 Annular region    -   7 Protrusions    -   8 Receiving members    -   9 Other side face    -   10 Spindle    -   11 Collar    -   12 First radial brush    -   13 Second radial brush    -   14 Flange disk    -   15 Screw slot    -   16 Annular region

1. A disk-shaped radial brush for grinding or polishing purposes,comprising a plate-shaped central body having two side faces and asubstantially central opening, and comprising a plurality of bristlesradially extending away from the central body, wherein the central bodyis provided with protrusions on at least one of the side faces and withcorresponding receiving members on the other side face.
 2. The radialbrush according to claim 1, wherein the protrusions on the one side faceand the receiving members on the other side face are circumferentiallyoffset with respect to each other.
 3. The radial brush according toclaim 1, wherein the protrusions and the receiving members are designedin a substantially elongated shape.
 4. The radial brush according toclaim 3, wherein the protrusions and the receiving members extend in asubstantially radial direction.
 5. The radial brush according to claim1, wherein the protrusions and the receiving members are disposedoutside of an annular region surrounding the central opening.
 6. Theradial brush according to claim 1, wherein the protrusions are combinedinto groups on the one side face.